1 /*
2 * PNX833x Hardware Watchdog Driver
3 * Copyright 2008 NXP Semiconductors
4 * Daniel Laird <daniel.j.laird@nxp.com>
5 * Andre McCurdy <andre.mccurdy@nxp.com>
6 *
7 * Heavily based upon - IndyDog 0.3
8 * A Hardware Watchdog Device for SGI IP22
9 *
10 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * based on softdog.c by Alan Cox <alan@redhat.com>
18 */
19
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/types.h>
25 #include <linux/kernel.h>
26 #include <linux/fs.h>
27 #include <linux/mm.h>
28 #include <linux/miscdevice.h>
29 #include <linux/watchdog.h>
30 #include <linux/notifier.h>
31 #include <linux/reboot.h>
32 #include <linux/init.h>
33 #include <asm/mach-pnx833x/pnx833x.h>
34
35 #define WATCHDOG_TIMEOUT 30 /* 30 sec Maximum timeout */
36 #define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */
37 #define PNX_WATCHDOG_TIMEOUT (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY)
38 #define PNX_TIMEOUT_VALUE 2040000000U
39
40 /** CONFIG block */
41 #define PNX833X_CONFIG (0x07000U)
42 #define PNX833X_CONFIG_CPU_WATCHDOG (0x54)
43 #define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58)
44 #define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c)
45
46 /** RESET block */
47 #define PNX833X_RESET (0x08000U)
48 #define PNX833X_RESET_CONFIG (0x08)
49
50 static int pnx833x_wdt_alive;
51
52 /* Set default timeout in MHZ.*/
53 static int pnx833x_wdt_timeout = PNX_WATCHDOG_TIMEOUT;
54 module_param(pnx833x_wdt_timeout, int, 0);
55 MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default="
56 __MODULE_STRING(PNX_TIMEOUT_VALUE) "(30 seconds).");
57
58 static bool nowayout = WATCHDOG_NOWAYOUT;
59 module_param(nowayout, bool, 0);
60 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
61 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
62
63 #define START_DEFAULT 1
64 static int start_enabled = START_DEFAULT;
65 module_param(start_enabled, int, 0);
66 MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion "
67 "(default=" __MODULE_STRING(START_DEFAULT) ")");
68
pnx833x_wdt_start(void)69 static void pnx833x_wdt_start(void)
70 {
71 /* Enable watchdog causing reset. */
72 PNX833X_REG(PNX833X_RESET + PNX833X_RESET_CONFIG) |= 0x1;
73 /* Set timeout.*/
74 PNX833X_REG(PNX833X_CONFIG +
75 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
76 /* Enable watchdog. */
77 PNX833X_REG(PNX833X_CONFIG +
78 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) |= 0x1;
79
80 pr_info("Started watchdog timer\n");
81 }
82
pnx833x_wdt_stop(void)83 static void pnx833x_wdt_stop(void)
84 {
85 /* Disable watchdog causing reset. */
86 PNX833X_REG(PNX833X_RESET + PNX833X_CONFIG) &= 0xFFFFFFFE;
87 /* Disable watchdog.*/
88 PNX833X_REG(PNX833X_CONFIG +
89 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) &= 0xFFFFFFFE;
90
91 pr_info("Stopped watchdog timer\n");
92 }
93
pnx833x_wdt_ping(void)94 static void pnx833x_wdt_ping(void)
95 {
96 PNX833X_REG(PNX833X_CONFIG +
97 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
98 }
99
100 /*
101 * Allow only one person to hold it open
102 */
pnx833x_wdt_open(struct inode * inode,struct file * file)103 static int pnx833x_wdt_open(struct inode *inode, struct file *file)
104 {
105 if (test_and_set_bit(0, &pnx833x_wdt_alive))
106 return -EBUSY;
107
108 if (nowayout)
109 __module_get(THIS_MODULE);
110
111 /* Activate timer */
112 if (!start_enabled)
113 pnx833x_wdt_start();
114
115 pnx833x_wdt_ping();
116
117 pr_info("Started watchdog timer\n");
118
119 return nonseekable_open(inode, file);
120 }
121
pnx833x_wdt_release(struct inode * inode,struct file * file)122 static int pnx833x_wdt_release(struct inode *inode, struct file *file)
123 {
124 /* Shut off the timer.
125 * Lock it in if it's a module and we defined ...NOWAYOUT */
126 if (!nowayout)
127 pnx833x_wdt_stop(); /* Turn the WDT off */
128
129 clear_bit(0, &pnx833x_wdt_alive);
130 return 0;
131 }
132
pnx833x_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)133 static ssize_t pnx833x_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
134 {
135 /* Refresh the timer. */
136 if (len)
137 pnx833x_wdt_ping();
138
139 return len;
140 }
141
pnx833x_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)142 static long pnx833x_wdt_ioctl(struct file *file, unsigned int cmd,
143 unsigned long arg)
144 {
145 int options, new_timeout = 0;
146 uint32_t timeout, timeout_left = 0;
147
148 static const struct watchdog_info ident = {
149 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
150 .firmware_version = 0,
151 .identity = "Hardware Watchdog for PNX833x",
152 };
153
154 switch (cmd) {
155 default:
156 return -ENOTTY;
157
158 case WDIOC_GETSUPPORT:
159 if (copy_to_user((struct watchdog_info *)arg,
160 &ident, sizeof(ident)))
161 return -EFAULT;
162 return 0;
163
164 case WDIOC_GETSTATUS:
165 case WDIOC_GETBOOTSTATUS:
166 return put_user(0, (int *)arg);
167
168 case WDIOC_SETOPTIONS:
169 if (get_user(options, (int *)arg))
170 return -EFAULT;
171
172 if (options & WDIOS_DISABLECARD)
173 pnx833x_wdt_stop();
174
175 if (options & WDIOS_ENABLECARD)
176 pnx833x_wdt_start();
177
178 return 0;
179
180 case WDIOC_KEEPALIVE:
181 pnx833x_wdt_ping();
182 return 0;
183
184 case WDIOC_SETTIMEOUT:
185 {
186 if (get_user(new_timeout, (int *)arg))
187 return -EFAULT;
188
189 pnx833x_wdt_timeout = new_timeout;
190 PNX833X_REG(PNX833X_CONFIG +
191 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = new_timeout;
192 return put_user(new_timeout, (int *)arg);
193 }
194
195 case WDIOC_GETTIMEOUT:
196 timeout = PNX833X_REG(PNX833X_CONFIG +
197 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE);
198 return put_user(timeout, (int *)arg);
199
200 case WDIOC_GETTIMELEFT:
201 timeout_left = PNX833X_REG(PNX833X_CONFIG +
202 PNX833X_CONFIG_CPU_WATCHDOG);
203 return put_user(timeout_left, (int *)arg);
204
205 }
206 }
207
pnx833x_wdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)208 static int pnx833x_wdt_notify_sys(struct notifier_block *this,
209 unsigned long code, void *unused)
210 {
211 if (code == SYS_DOWN || code == SYS_HALT)
212 pnx833x_wdt_stop(); /* Turn the WDT off */
213
214 return NOTIFY_DONE;
215 }
216
217 static const struct file_operations pnx833x_wdt_fops = {
218 .owner = THIS_MODULE,
219 .llseek = no_llseek,
220 .write = pnx833x_wdt_write,
221 .unlocked_ioctl = pnx833x_wdt_ioctl,
222 .open = pnx833x_wdt_open,
223 .release = pnx833x_wdt_release,
224 };
225
226 static struct miscdevice pnx833x_wdt_miscdev = {
227 .minor = WATCHDOG_MINOR,
228 .name = "watchdog",
229 .fops = &pnx833x_wdt_fops,
230 };
231
232 static struct notifier_block pnx833x_wdt_notifier = {
233 .notifier_call = pnx833x_wdt_notify_sys,
234 };
235
watchdog_init(void)236 static int __init watchdog_init(void)
237 {
238 int ret, cause;
239
240 /* Lets check the reason for the reset.*/
241 cause = PNX833X_REG(PNX833X_RESET);
242 /*If bit 31 is set then watchdog was cause of reset.*/
243 if (cause & 0x80000000) {
244 pr_info("The system was previously reset due to the watchdog firing - please investigate...\n");
245 }
246
247 ret = register_reboot_notifier(&pnx833x_wdt_notifier);
248 if (ret) {
249 pr_err("cannot register reboot notifier (err=%d)\n", ret);
250 return ret;
251 }
252
253 ret = misc_register(&pnx833x_wdt_miscdev);
254 if (ret) {
255 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
256 WATCHDOG_MINOR, ret);
257 unregister_reboot_notifier(&pnx833x_wdt_notifier);
258 return ret;
259 }
260
261 pr_info("Hardware Watchdog Timer for PNX833x: Version 0.1\n");
262
263 if (start_enabled)
264 pnx833x_wdt_start();
265
266 return 0;
267 }
268
watchdog_exit(void)269 static void __exit watchdog_exit(void)
270 {
271 misc_deregister(&pnx833x_wdt_miscdev);
272 unregister_reboot_notifier(&pnx833x_wdt_notifier);
273 }
274
275 module_init(watchdog_init);
276 module_exit(watchdog_exit);
277
278 MODULE_AUTHOR("Daniel Laird/Andre McCurdy");
279 MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x");
280 MODULE_LICENSE("GPL");
281 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
282